<!DOCTYPE html> 
 <html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>定位和布局</title>
</head>
<style>
    #root {
        width: 100%;
        height: 100%;
        background-color: aliceblue;
    }
</style>
<body>
    <div id="root">
        <button>点我获取数据</button>
    </div>
</body>

</html>